Recent research from Edith Cowan University (ECU) has illuminated the potential impact of diet on the risk factors for both depression and Alzheimer’s disease (AD). The study indicates that depressive symptoms might not only predict the onset of AD but also respond to the early signs of memory decline. Dr Samantha Gardener, a researcher at ECU, highlighted how maintaining healthy dietary patterns could mitigate the adverse effects depressive symptoms have on changes in AD-related blood-based biomarkers, which are biological molecules in the blood used to track the progression of the disease.
The research contributes valuable insights into the complex interactions between diet, depressive symptoms, and AD-related biomarkers. Dr. Gardener explained that dietary factors influence brain health through inflammation, oxidative stress, vascular function, neuroplasticity, and the gut-brain axis. These pathways potentially affect neurotransmitter systems and neuronal functions, subsequently impacting mood and cognitive functions. The findings underscore the significant role that diet may play in managing and potentially preventing mental health and neurodegenerative conditions.
Particularly noteworthy is the comparison between the Mediterranean diet and the typical Western diet. The Mediterranean diet, rich in plant foods, olive oil, whole grains, and a moderate intake of red wine, is associated with lower risks of stroke, depression, cognitive impairments, and AD. In contrast, a Western diet, characterized by high amounts of processed foods and sugars, is linked to accelerated decline in brain function. Dr. Gardener emphasized the richness of the Mediterranean diet in antioxidants, flavonoids, and healthy fatty acids, which are essential for reducing brain inflammation and oxidative stress and crucial for learning and memory.
Despite the promising observational studies, Dr. Gardener stressed the importance of conducting randomized controlled trials. These trials are essential to explore the specific effects of dietary interventions on depression and dementia due to AD, providing more definitive evidence on the effectiveness of targeted nutritional interventions in managing these conditions.
Globally, Alzheimer’s disease is a significant public health issue, affecting approximately 50 million people, with projections suggesting an increase to 152 million by 2050. The financial impact of AD and other dementia-related conditions is enormous, estimated at $909 billion annually, which is about 1% of the global gross domestic product. In Australia alone, around $3.7 billion is spent annually on the diagnosis, treatment, and care of individuals with dementia, highlighting the economic burden of these conditions.
Dr. Gardener pointed out that delaying the onset of AD could significantly reduce its prevalence and public health impact. Research has identified 14 modifiable risk factors that account for around 45% of dementia cases worldwide, five of which can be positively influenced by a healthy diet, including hypertension, obesity, alcohol intake, and depression. She concluded that addressing these risk factors, enhancing physical activity, and ensuring sufficient sleep could potentially prevent nearly 45% of dementia cases, underscoring the profound potential of lifestyle interventions in public health.
More information: Samantha Gardener et al, The moderating effect of diet on the relationship between depressive symptoms and Alzheimer’s disease-related blood-based biomarkers, Neurobiology of Aging. DOI: 10.1016/j.neurobiolaging.2025.01.003
Journal information: Neurobiology of Aging Provided by Edith Cowan University
